Women taking antipsychotic medications during pregnancy did not have increased incidence of pregnancy complications, a new study found. These results may be reassuring to women who are using these medications to treat conditions such as schizophrenia, bipolar disorder and major depression.

The study by researchers at Women’s College Hospital (WCH) and the Institute for Clinical Evaluative Sciences (ICES) looked at newer antipsychotics, primarily quetiapine, olanzapine and risperidone.

“The newer antipsychotic medications, which have only been on the market since the early 1990s, have not been extensively studied for impact on women during pregnancy, or on the child,” says lead study author Dr. Simone Vigod, a scientist with Women’s College Research Institute and an adjunct scientist with ICES.

“The question we set out to answer with this study is whether taking antipsychotic medications during pregnancy increases risk for certain maternal conditions during pregnancy, or risk for certain infant or fetal concerns, compared to not taking antipsychotic medications during pregnancy.”

Dr. Vigod and her colleagues used a method called high dimensional propensity score to match 1,021 pregnant women taking antipsychotics with a control group of 1,021 similar pregnant women. They then compared outcomes in the two groups. The main difference between the groups was that one was taking antipsychotics and the other was not. To be in the medication group, women had to have filled at least two consecutive prescriptions for antipsychotics during pregnancy. At least one of the prescriptions had to be filled during the first or second trimester.

There were no significant differences between the two groups in incidence of gestational diabetes, venous thromboembolism (blood clots), or pregnancy-related blood pressure disorders such as high blood pressure and preeclampsia. The women taking antipsychotics also had no increased risk of preterm birth, or of extremely low or extremely high birth weight, compared to the control group.

The study did find that women using antipsychotic drugs were more likely to require induced labour or operative vaginal delivery.

These results suggest that risks linked to antipsychotic drug use during pregnancy are minimal. These findings should reassure women who use these medications. They should also help guide healthcare providers who treat these women.

However, the study authors note that incidence of pregnancy complications in both the group taking antipsychotics and in the control group were higher than what is seen in the general population. They recommend closely monitoring these women’s health before and during pregnancy.